With the development of the globalization economic integration in Internet of Things (IoT), it is very crucial to protect the wireless two-way authentication between users’ intelligent terminals and servers in the product authorization chain. In order to ensure that legitimate users connect to the wireless network correctly, a lightweight wireless mutual authentication scheme for the product authorization chain was proposed contrapose to the security defect of Kaul and Awasthi’s scheme, which easily suffered from offline password guessing attack. The improved scheme uses lightweight hash function and verifies the freshness of messages by using the send packet sequence number instead of timestamp, which can avoid strict clock synchronization between devices, and user passwords can be updated by themselves. Security analysis and cost and efficiency analysis show that the scheme presented in this paper has higher security, lower storage and communication costs, and lower computational complexity.

Orthogonal frequency division multiplexing‐based pattern division multiple access (PDMA) is considered as a promising multiple access scheme for future wireless communication systems due to its high spectral efficiency and powerful ability to support massive users. In this study, it is shown that two pattern matrices with unequal diversity gain in the PDMA system have better convergence performance compared with the signature matrices in a traditional low‐density signature multiple access system by simulations and extrinsic information transfer (EXIT) chart analysis. For a low‐density parity check (LDPC)‐coded PDMA system, the EXIT characteristics between the front‐end multiple‐user detector (MUD) and the LDPC decoder may be mismatch, which usually leads to degraded performance when an iterative detection and decoding algorithm is used. To overcome this problem, a two‐stage iterative optimisation algorithm, which is easy to implement is proposed to find an optimal (near optimal) degree distribution pair for the LDPC code. Both EXIT chart analysis and simulation results demonstrate that the proposed algorithm exhibits further performance gain compared with regular (3,6) LDPC‐coded systems under both an additive white Gaussian noise channel and a Rayleigh fading channel.